Sulfur-hydrocarbon slurry pipeline transportation containing organic inhibitors

ABSTRACT

An improved method of transporting sulfur-liquid hydrocarbon slurries through pipelines without causing plugging or corrosion of the pipelines. The invention relates to an improved and novel process of preventing plugging and corrosion of pipelines transporting sulfur in the form of a sulfur-liquid hydrocarbon slurry.

United States Patent I 72] Inventor Mary Frances Vondrak Houston, Tex.

[2|] Appi. No. 772,010

[22l Filed Oct. 30, 1968 [45] Patented Aug. 3, I97] I73 Assignee Shell Oil Comapny New York, N.Y.

[54] SULFUR-HYDROCA RBON SLURRY PIPELINE TRANSPORTATION CONTAINING ORGANIC INHIBITORS 10 Claims, No Drawings [52] US. Cl 302/66 [SI Int. Cl 865g 53/04 [50] FieldofSeai'ch 302/14, [5. i6, 66

[56] References Cited UNITED STATES PATENTS 2,798,772 7/1957 Redcay Primary Examiner-Andres H. Neilsen AltorneysGeorge G. Pritzker and .l H. McCarthy SULIIJIR-IIYDROCAIIBON SLUIIIII lPIlPlElLINE TRANSPORTATION CONTAINING OIIGANIC INHIBITORS BACKGROUND OF THE INVENTION The transportation of sulfur neat or as a water or oil slurry in pipelines is well known in the art as noted by reference to U.S. Pat. Nos. 2,798,772; 2,9l7,345 or 2,947,578 or as described in Pipeline Industry, June, i967, pages 58-60. In making the sulfur into a sulfur-hydrocarbon slurry, the sulfur is generally sprayed in molten form into either water or a hydrocarbon to form a etc., suitable for transportation through a pipeline. Formation of a stable slurry wherein the sulfur does not undergo any undesirable change or the slurry does not exhibit a tendency to wide variation in viscosity is essential to the process in addition to other problems which may be encountered during and after transportation of the slurry through a pipeline. Thus, separation of the sulfur from the carrier fluid, plating or coating of the sulfur on pipeline walls causing plugging of the pipeline, corrosion, viscosity changes due to pressure and temperature variations encountered requiring increases in pumping power which increases opera tion costs, etc., are only a few of the problems normally encountered in transporting sulfur-liquid hydrocarbon slurries through pipelines.

Although the above are serious problems for consideration in transporting sulfur through pipelines, nevertheless the transportation ofsulfur in slurry form through pipelines can be made to be an effective, attractive and economic means of transportation, particularly since sulfur is recovered or obtained from isolated, remote and inaccessible areas, and must be transported to desired accessible areas. As noted above, a number of methods have been proposed for pipeline transportation of sulfur slurries such as injecting molten sulfur into water or a liquid hydrocarbon thereby forming a sulfur slurry for pipeline transportation. Such means for transporting sulfur generally do not overcome the corrosion, coating and/or plugging problems described above.

An object of the present invention is to transport sulfur as a sulfur-liquid hydrocarbon slurry through pipelines which is stable and flowable.

Another object of the present invention is to transport through a pipeline sulfur-liquid hydrocarbon slurries without causing sulfur coating, deposition or plugging or corrosion of the pipeline.

Still another object of this invention is to form a slurry of sulfur in a liquid hydrocarbon medium, which when formed is stable, noncorrosive, does not tend to cause pipeline plugging when said slurry is transported through a pipeline and from which the sulfur can be readily recovered as essentially pure sulfur.

Another object is to transfer sulfur as a liquid hydrocarbon slurry by pipeline over great distances reducing pumping and handling costs.

Other objects will be apparent from the following descriptron.

SUMMARY OF THE INVENTION t liquid hydrocarbon slurry into the pipeline, a small amount of from 0.1 to percent by weight, preferably between about 0.5 to about 5 percent by weight, of an aqueous solution basis total slurry and from about 5 to about 5,000 ppm. basis oil phase of an oil-solution nitrogen-containing organic compound having at least one amino or aminoamide or imidozole group in the molecule and also possessing a slight degree of water solubility, although this is not an essential feature of this class of additives. A nitrogen-containing compound as defined should be present in the final mixture in an amount preferably not exceeding 1,000 ppm. basis oil phase and the additive can be injected when necessary in various places along the pipeline where indications are that corrosion or plugging of the line might take place. Any corrosion and plugging detection means known in the art can be used for this purpose. it has been noted that by injection of l5percent by weight of an aqueous solution basis total slurry and a small amount (5 1,000 ppm. basis oil phase) of a nitrogen-containing compound as defined into a pipeline transporting a sulfur-liquid hydrocarbon slurry in which the sulfur content of the slurry can vary from about 10 percent by weight to about 75 percent by weight or higher, preferably between 40 and 70 percent by weight sulfur, inhibits corrosion and prevents plugging of the line due to sulfur deposition on the: walls of the pipeline, resulting in improved flow of the slurry at reduced pumping cost. A preferred plugging and corrosion preventing composition for sulfur-liquid hydrocarbon slurries being pipeline transported is the addition to such slurries of from about i to 5 percent by weight water basis total slurry and 5 l ,000 ppm. basis oil phase of an oil-soluble nitrogen-containing compound selected from the group consisting of oil-soluble amino- ,aminoamide-, imidazole-containing compounds and mixtures thereof as well as quaternary ammonium salts, salts and quaternary derivatives of amino amides, salts and quaternary derivatives of imidazolines, salts and quaternary derivatives of aminoesters, diamine naphthenates, hydrolyzed acid amines and oxyethylated amines and amides. The oil-soluble amino compound includes salts and esters of long chain fatty polyamine such as tallow diamine hydrolyzed acid available under the trade name of Wellaid 630, 651 and 652 (Amoco Chemical Company) or tallow diamine naphthenate available under the trade name of Wellaid 601 and 602 (Amoco Chemical Company); and aminoamide compounds such as are available under the trade name of Visco 928, or the quaternary amine compounds, e.g., Visco 937 (Nalco Chemical Company) and the imidazoline compounds available under the trade name of Kontol 148 or (Tretolite Corporation) or Magna 63, 66A,828 or 829 (Magna Chemical Company) and l-ethylhydroxyl-2tallowimidazole, available under the trade name Hodag C- l 00-T from the Hodag Chemical Corporation.

The sulfur-liquid hydrocarbon slurry can be made by any suitable means such as described in U.Si. Pat. No. 2,798,772 or by the method described in copending patent application Ser. No. 663,755, filed Aug. 28, 1967 which matured as U.S. Pat. No. 3,443,837. It is preferred that methods for making the sulfur-liquid hydrocarbon slurry be used in which the sulfur is produced in spherical form since this facilitates the stable dispersion and suspension of the sulfur in the liquid hydrocarbon carrier and inhibits attrition and reduces friction. The phase transfer method for making the sulfur slurry as described in the above copending application comprises first forming a sulfur-aqueous liquid (water) slurry and thereafter phase transferring the sulfur particles from the aqueous liquid into a liquid hydrocarbon. In this process the phase transformation to form the sulfur-hydrocarbon slurry can be so controlled that a small amount (l-S percent by weight) water basis total slurry is transferred with the sulfur-water phase into the hydrocarbon phase and thereafter a nitrogen-containing compound as defined can be added to accomplish the desired ends of the present invention.

The hydrocarbon carrier for the sulfur can be any liquid hydrocarbon ranging from a light petroleum fraction such as liquefied petroleum gas (LPG), fuel oil, gasoline, kerosene, petroleum distillates, condensates, crude oil and mixtures thereof. Preferred are liquid hydrocarbons containing at least 10 percent by weight or higher or aromatics, preferably about l5-30 percent by weight aromatic enriched kerosene or crude oil or crude oil condensate fractions containing l5-20 percent by weight aromatics which include monoand polyaromatic hydrocarbons.

At the terminal end of the line the aqueous solution can be readily separated from the sulfur-hydrocarbon system by suitable phase separation, distillation or the like.

PREFERRED EMBODIMENT OF THE INVENTION prepared by phase transfer by first injecting molten sulfur into 10 an aqueous liquid such as water and thereafter contacting the slurry thus formed with hydrocarbons (a), (b) or (c) to effect phase transfer of the sulfur particles into the hydrocarbon, and injecting this slurry into a pipeline followed by injection of 2 percent by weight water basis oil phase and about 5- l,000 p.p.m. basis oil phase of the nitrogen-containing additive shown in table 2 and table 3. Sulfur-hydrocarbon slurries thus formed in the presence of the water and a nitrogen-containing additive of the present invention do not corrode or plug pipelines. Instead of using the phase transfer technique for making the slurry, the molten sulfur can be injected in the hydrocarbons (a), (b) or (c) directly and thereafter admixed with the aqueous solution and additive.

- An advantage of the present process for transporting through pipelines sulfur-liquid hydrocarbon slurries is that the slurry can be also prepared by directed injection of molten sulfur into a suitable liquid hydrocarbon as described in U.S. Pat. No. 2,798,772 and injecting therein a small amount of water and nitrogen-containing additive so as to prevent corrosion and plugging of the line. Either process as well as other processes can be used to make the sulfur-liquid hydrocarbon v slurry depending on the availability of the liquid carriers.

Thus; where water is available the first process can be used and if not, the second one can be used.

The corrosive effect of added or adventitious water on sulfur-liquid hydrocarbon slurries is evident from the data presented in table 1 and the selectiveness and unexpected effect of nitrogen-containing additives of this invention as corrosion preventive agents is shown in table 2 and table 3.

The slurry tested comprised 40 percent by weight sulfur and 60 percent by weight hydrocarbon and the conditions for the corrosion test were as follows:

CORROSION BY SULFUR SLURRIES Conditions:

One hundred fifty ml. magnesia bottles rotated at r.p.m.

in bottle rotator, 48 hours.

one hundred twenty ml. of slurry added to each bottle.

Slurry concentration 40 percent by weight sulfur.

Sulfur particle size: Waterton sulfur 82 percent greater than 45 microns. Jumping Pound sulfur 81 percent greater than 45 microns,

Oil phase: Note tables I, 2 and 3.

Water additions are percent by weight of oil fraction.

lxfil-inch' specimens of ZO-guage mild steel sheet with sandblasted surface. Specimens wedged into bottles to reduce mechanical damage.

Room temperature, atmospheric pressure.

Table l SULFUR SLURRY CORROSION AS A FUNCTION OF WATER CONCENTRATION Conditions: As given above. 40iw Waterton sulfur/kerosene with l7iiw aromatics Water Concentration. Qw" Corrosion Rate. mils/yr.

0 I 0.14 7 0.28 50 I.I2 I 2.2 230 4.4 250 5.0 280 a) Concentration ofadded water. basis oil.

b) From weight loss and exposure time. Corrosion rates have not been corrected for weight loss due to cleaning.

Table 2 EFFECT OF ORGANIC INHIBITORS ON SULFUR SLURRY CORROSION Conditions: Jumping Pound sulfur, oil phase as indicated. Aerated. Other experimental conditions as shown above. All slurries have 2% by weight water added basis oil phase.

Additive" Concentration p.p.m." Corrosion Rate, mpy" Oil Phase: Kerosene with 17% by weight aromatics (a) Magna 829" Wellaid 60 I Wellaid 602" Wellaid 65I" Wellaid 652'" Wellaid 630 Oil Phase: Waterton Condensate (b) Kontol I48'" I 3 4 Magna 828'" I90 4 95 5 Magna 63'" I90 4 95 5 Hodag C-IOO-T" I90 5 95 4 40 4 Oil Phase: Hydrocarbon Blend (c) KontOI I48 I00 4 45 5 Magna 828'" I00 5 45 4 Magna 63'" I00 5 45 6 Hodag C-IOO-T I00 4 45 5 a) All slurries contained 2 '11 by weigh gwater (basis oil).

b) The concentration is calculated by volume based on the oil.

c) From weight loss and exposure time. Corrosion rates have not been corrected for weight loss due to cleaning.

d) An imidazoline.

e l A tallow diamine naphthenale. oil soluble water insoluble.

f) A tallow diamine naphthenate, oil soluble -water dispersible.

g l A tallow diamine hydrolyzed acid. oil soluble water insoluble.

h l A tallow diamine hydrolyzed acid, oil soluble water dispersible.

-ethylhydroxyl-2 -tallowimidazole.

Table 3 ORGANIC INHIBITORS FOR SULFUR SLURRY CORROSION Conditions: Experimental conditions are described above. All slurries contain 2% by weight H,0 basis oil phase and hydrocarbon is a kerosene with l7iw aromatics.

Additive Concentration p.p.m." Corrosion Rate, mpy

Kontol I75 Visco 928'" Visco 937" Magna 63" Magna lib-A" Magna 828" Magna 829" l'lodlg C- I 00-T" a The concentration is calculated by volume based on the oil.

b) From weight loss and exposure time. Parenthesis indicates corrosion due to maximum pit depth observed. Corrosion rates have not been corrected for Weight loss due to cleaning.

c) An imidnzolinev d) Amino amide.

e) Quaternary amine.

fl l

ethylhydroxyl-Z -tallowimidazole.

it the tenninalend of the line the water phase as; Benin ly removed by phase separation and the sulfur can be removed from the liquid hydrocarbon by suitable means such as described in U.S. Pat. No. 2,798,772 and the sulfur purified by methods as described in U.S. Pat. No. 2,809,885 or as described in the copending patent application Ser. No. 684,507, filed Nov. 20, 1967 which matured as U.S. Pat. No. 3,489,677 which comprises treating oil-contaminated sulfur with an aqueous solution containing a mixture of alkali hydrosulfide and corresponding hydroxide, e.g., ammonium hydrosulfide and ammonium hydroxide, or by other suitable means such as sulfur can be recovered from the oil slurry by filtration of molten sulfur and liquid-liquid extraction with a hydrocarbon solvent containing 10-50 percent by weight aromatic. Thus, at the receiving terminal the sulfur slurry can be filtered and washed. The recovered sulfur is then melted and purified by liquid-liquid extraction with an aromatic hydrocarbon such as cumene. Also, if desired, the filtered sulfur can be steam stripped to recover bright yellow sulfur.

The foregoing description of the invention is merely intended to be explanatory thereof. Various changes in the details of the described method may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim as my invention:

1. A method of transporting sulfur through a pipeline to a terminal preventing corrosion and without plugging the line comprising:

a. injecting from 10 percent to 75 percent of molten sulfur into a liquid hydrocarbon to form a sulfur-liquid hydrocarbon slurry;

b. mixing slurry (a) with from 0.1 percent to 10 percent of an aqueous solution containing from about 5 to about 1,000 p.p.m. of an oil-soluble nitrogen-containing organic compound;

c. injecting the slurry (a) and solution (b) into a pipeline;

and,

d. transporting the sulfur-hydrocarbon slurry and aqueous solution mixture through a pipeline to a terminal station.

2. The method of claim 1 wherein the liquid hydrocarbon of (a) contains from 10 percent to 30 percent aromatic components and the nitrogen-containing compound is selected from the group consisting of oil-soluble amino-, quaternary amino-, aminoamide-, imidazole-containing compounds.

3. The method of claim 1 wherein solution (b) is injected into the slurry (a) after the slurry (a) has been injected into a pipeline.

4. The method of claims 1 and 3 wherein the slurry (a) contains 10-75 percent by weight sulfur and the balance being a liquid hydrocarbon containing aromatic components and the amount of mixture (b) added to slurry (a) is from 0.1 to 10 percent by weight water basis total slurry and from 5 to 1,000 p.p.m. of the nitrogen-containing organic compound basis oil phase.

5. The method of claim 4 wherein mixture (b) is water containing 5l,000 p.p.m. of an imidazoline basis oil phase admixed with slurry (a) in amounts of from I to 5 percent by weight basis total slurry.

6. The method of claim 4 wherein mixture b) is water containing 5l,000 p.p.m. of a polyamine basis oil phase admixed with slurry (a) in amounts of from I to 5 percent by weight basis total slurry.

7. The method of claim 4 wherein mixture (b) is water containing 5l,000 p.p.m. of an aminoamide basis oil phase admixed with slurry (a) in amounts of from 1 to 5 percent by weight basis total slurry.

8. The method of claim 4 wherein mixture (b) is water containing 5- l ,000 p.p.m. of a quaternary amine basis oil phase admixed with slurry (a) in amounts of from I to 5 percent by weight basis total slurry.

9. The method of claim 4 wherein mixture (b) is water containing 5-l,000 p.p.m. of a 1-ethylhydroxyl-2'tallowimidazole basis oil phase admixed with slurry (a) in amounts of from 1 to 5 percent by weight basis total slurry.

10. The method of" claim 1 wherein the sulfur-liquid hydrocarbon slurry is separated into its component parts at the terminal station. 

2. The method of claim 1 wherein the liquid hydrocarbon of (a) contains from 10 percent to 30 percent aromatic components and the nitrogen-containing compound is selected from the group consisting of oil-soluble amino-, quaternary amino-, aminoamide-, imidazole-containing compounds.
 3. The method of claim 1 wherein solution (b) is injected into the slurry (a) after the slurry (a) has been injected into a pipeline.
 4. The method of claims 1 and 3 wherein the slurry (a) contains 10-75 percent by weight sulfur and the balance being a liquid hydrocarbon containing aromatic components and the amount of mixture (b) added to slurry (a) is from 0.1 to 10 percent by weight water basis total slurry and from 5 to 1,000 p.p.m. of the nitrogen-containing organic compound basis oil phase.
 5. The method of claim 4 wherein mixture (b) is water containing 5-1,000 p.p.m. of an imidazoline basis oil phase admixed with slurry (a) in amounts of from 1 to 5 percent by weight basis total slurry.
 6. The method of claim 4 wherein mixture (b) is water containing 5-1,000 p.p.m. of a polyamine basis oil phase admixed with slurry (a) in amounts of from 1 to 5 percent by weight basis total slurry.
 7. The method of claim 4 wherein mixture (b) is water containing 5-1,000 p.p.m. of an aminoamide basis oil phase admixed with slurry (a) in amounts of from 1 to 5 percent by weight basis total slurry.
 8. The method of claim 4 wherein mixture (b) is water containing 5-1,000 p.p.m. of a quaternary amine basis oil phase admixed with slurry (a) in amounts of from 1 to 5 percent by weight basis total slurry.
 9. The method of claim 4 wherein mixture (b) is water containing 5-1,000 p.p.m. of a 1-ethylhydroxyl-2-tallowimidazole basis oil phase admixed with slurry (a) in amounts of from 1 to 5 percent by weight basis total slurry.
 10. The method of claim 1 wherein the sulfur-liquid hydrocarbon slurry is separated into its component parts at the terminal station. 